1. Technical Field
The present invention relates to an electronic device, an electronic apparatus, a moving object, and a method for manufacturing an electronic device.
2. Related Art
As an example of piezoelectric oscillators including a piezoelectric resonator, there is a crystal oscillator including a quartz crystal resonator. As typical configurations for obtaining frequency stability against the temperature of the quartz crystal oscillator, a temperature compensated crystal oscillator (TCXO) and an oven controlled crystal oscillator (OCXO) have been known. The TCXO is configured such that a temperature compensated circuit using a thermosensor is incorporated to correct an oscillating frequency based on the temperature detected value of the thermosensor. The TCXO has advantages in that it has low power consumption, and is generally small in size and light in weight, compared to the OCXO described later. However, the TCXO is susceptible to an ambient temperature compared to the OCXO, and therefore, it is difficult to apply the TCXO when high frequency-stability is required.
On the other hand, the OCXO has a structure in which a quartz crystal resonator is at a constant temperature by heating with a heating element such as, for example, a heater to maintain the constant ambient temperature of the quartz crystal resonator. However, the OCXO needs a structure to reduce the power consumption of the heater by preventing the heat of the quartz crystal resonator from escaping to the outside.
Japanese Patent No. 4804813 (Patent Document 1) discloses a configuration in which a quartz crystal resonator to which a resistance heating element and a thermosensor are attached is connected to a board via a lead frame to thereby be supported by the lead frame in a state where the quartz crystal resonator floats above the board. JP-A-2010-199678 (Patent Document 2) discloses the following configuration. An electrode of a quartz crystal resonator accommodated in a package is connected to a through-electrode formed in the package, and a lead frame is connected to a portion of the package where the through-electrode is exposed. The package is connected to a board via the lead frame, so that the package is supported in a state of floating above the board. With the configuration disclosed in Patent Document 1, it is possible to reduce the conduction of heat of the quartz crystal resonator to the board side. With the configuration disclosed in Patent Document 2, it is possible to reduce the conduction of heat of the package including the quartz crystal resonator to the board side.
In the related art, however, in the connection between the electrode of the quartz crystal resonator and the lead frame and in the connection between the electrode on the board and the lead frame, the bonding area of the lead frame is the width of the lead frame itself at most. Therefore, the connection strength may be insufficient. For increasing the connection strength between the quartz crystal resonator and the lead frame, there is a method of disposing a castellation in the quartz crystal resonator to forma fillet at a connecting portion between the quartz crystal resonator and the lead frame. This method can increase the connection strength between the quartz crystal resonator and the lead frame, but the strength of the quartz crystal resonator itself may be lowered because a recess is disposed in the quartz crystal resonator, that is, the package by disposing the castellation.